/**
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package com.google.wave.splash.web.stats;

import com.google.inject.Inject;
import com.google.inject.Singleton;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

/**
 * A filter that times an entire request.
 *
 * @author David Byttow
 */
@Singleton
class TimingFilter implements Filter {
  private static final int DEFAULT_REQUEST_TIME_THRESHOLD = 500;

  private final Timing timing;

  @Inject
  TimingFilter(Timing timing) {
    this.timing = timing;
  }

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest req = (HttpServletRequest) request;
    timing.start(req.getRequestURI());
    try {
      chain.doFilter(req, response);
    } finally {
      timing.stop(req.getRequestURI(), DEFAULT_REQUEST_TIME_THRESHOLD, req.getRequestURI());
    }
  }

  @Override
  public void init(FilterConfig unused) {
  }

  @Override
  public void destroy() {
  }
}
